The Three Super-Earths of Gliese 677C; and Unexpected Planets

Five newly-discovered planets stood out in this week's news. Two were in an unexpected place, three should be warm enough to have liquid water on the surface: If they're made of stuff like the Solar system's inner planets, that is, and have an atmosphere.

1. Two Unexpected Planets
   • A New Kind of Planet?
2. Three Super-Earths: Each in the Habitable Zone
3. Rocky, Maybe: Life, Could Be

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New Planets Discovered: A Matter of Routine

These days, astronomers add newly-discovered planets to rapidly-growing lists like Caltech's Jet Propulsion Laboratory's New Worlds Atlas: but since 'new planet discovered' is now a routine matter, few get attention in the news.

Seeking Truth

I like living in a world where robot spaceships explore the Solar system while astronomers assemble catalogs of potential destinations for interstellar exploration.

Sure, we have trouble here on Earth. That's what happens when free-willed creatures decide that we'd rather do things our way, than the right way: and that's another topic. (July 11, 2012)

I'm very concerned about several issues, but I'm also fascinated by this universe. My faith doesn't require that I keep up with developments in science, but I don't see a conflict between seeking truth and seeking God. (February 3, 2013)

"Faith and science: 'Though faith is above reason, there can never be any real discrepancy between faith and reason. Since the same God who reveals mysteries and infuses faith has bestowed the light of reason on the human mind, God cannot deny himself, nor can truth ever contradict truth.'... the things of the world and the things of faith derive from the same God...."
(Catechism of the Catholic Church, 159)

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"Basic scientific research, as well as applied research, is a significant expression of man's dominion over creation. Science and technology are precious resources when placed at the service of man and promote his integral development for the benefit of all....

"...It is an illusion to claim moral neutrality in scientific research and its applications. ... Science and technology by their very nature require unconditional respect for fundamental moral criteria. They must be at the service of the human person, of his inalienable rights, of his true and integral good, in conformity with the plan and the will of God."
(Catechism, 2293-2294)

In this case, "moral criteria" are not zipper issues. I've discussed ethics and getting a grip before. (June 3, 2011)

Planets, Life, and New Civilizations

The mission of Star Trek's Enterprise was "...to seek out new life and new civilizations...." I've run into quite a few opinions about finding "new life" elsewhere in the universe.

Some folks seem to think that the universe isn't particularly lively. One book even came close to demonstrating that life couldn't get started on Earth. Others apparently assume that space aliens are just about everywhere, although I gather that flying saucers aren't the hot topic they were in 1947.

If there are other folks like us, free-willed creatures with material bodies, that will be an opportunity to compare notes. We can start sorting out how much of 'human nature' is simply what happens with our sort of spirit-matter hybrids; and how much is specific to the particular sort of hairy biped that we are.

It's possible, though, that we're the only people in this universe. If that's the case, we'll be building those "new civilizations."

Other Worlds

Wondering about other worlds isn't particularly new. More than seven hundred years back, some serious thinkers decided that since Aristotle didn't think other worlds existed: they didn't.

It's been against the rules for Catholics to say there can't be other worlds like ours - since 1277. (January 29, 2012)

Terraforming

There's almost certainly going to be another heated debate eventually, when someone wants to terraform another planet: adjust its atmosphere and surface until it'll support our sort of life.

My guess is that Venus might be the first proposed site. It's about the same size as Earth, although that overheated atmosphere would be an issue: and it's right here in the Solar system.

Happily, that's an issue that I won't have to deal with: not unless technology develops a whole lot faster than I think it will.

Ethics will be an issue, as they are with anything we do. But I don't see anything basically wrong with continuing to act as stewards of God, working with this creation to improve the lives of ourselves and out neighbors. Existing literature talks about this stewardship in terms of "the earth," with a lower case "e," but also refers to "the goods of creation." (Catechism of the Catholic Church, 373, 2402)

We're discovering that creation extends far beyond this planet we call Earth: and that brings me to the first news item.

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1. Two Unexpected Planets

"First transiting planets in a star cluster discovered"
Elizabeth Howell, Phys.org (June 26, 2013)

"All stars begin their lives in groups. Most stars, including our Sun, are born in small, benign groups that quickly fall apart. Others form in huge, dense swarms that survive for billions of years as stellar clusters. Within such rich and dense clusters, stars jostle for room with thousands of neighbors while strong radiation and harsh stellar winds scour interstellar space, stripping planet-forming materials from nearby stars.

"It would thus seem an unlikely place to find alien worlds. Yet 3,000 light-years from Earth, in the star cluster NGC 6811, astronomers have found two planets smaller than Neptune orbiting Sun-like stars. The discovery, published in the journal Nature, shows that planets can develop even in crowded clusters jam-packed with stars...."

Maybe those planets formed around some of the first stars formed in that cluster, before the place heated up. In any case, astronomers are re-examining their ideas about how stars and planets form.

That's nothing new. An individual scientist might have absolute certainty that a particular explanation for how things happen is right. That sort of cocksure attitude seems to be more common among 'science reporters' and folks with a book to sell.

When I started reading what scientists write, not what reporters write about them, I realized that revising theory to fit observation, or scrapping last year's explanations entirely when the facts don't fit, is routine. I suspect it's occasionally frustrating, and that's yet another topic.

A New Kind of Planet?

"...'Old clusters represent a stellar environment much different than the birthplace of the Sun and other planet-hosting field stars,' says lead author Soren Meibom of the Harvard-Smithsonian Center for Astrophysics (CfA). 'And we thought maybe planets couldn't easily form and survive in the stressful environments of dense clusters, in part because for a long time we couldn't find them.'

"The two new alien worlds appeared in data from NASA's Kepler spacecraft. Kepler hunts for planets that transit, or cross in front of, their host stars. During a transit, the star dims by an amount that depends on the size of the planet, allowing the size to be determined. Kepler-66b and Kepler-67b are both less than three times the size of Earth, or about three-fourths the size of Neptune (mini-Neptunes)...."
(Elizabeth Howell, Phys.org)

Discovering that planets were fairly common was exciting. So is learning that some planets seem to be something that's not the small rocky variety found close to our star, like Mercury through Mars; or the big gaseous sort found outside the Asteroid Belt.

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2. Three Super-Earths: Each in the Habitable Zone

(ESO/M. Kornmesser, via BBC News, used w/o permission)
"An impression of what the sky might look like from the exoplanet Gliese 667Cd, looking towards the parent star and featuring, at top, the other super-Earths in the habitable zone"

"Star is crowded by super-Earths"
Jonathan Amos, BBC News (June 25, 2013)

"Scientists have identified three new planets around a star they already suspected of hosting a trio of worlds.

"It means this relatively nearby star, Gliese 667C, now has three so-called super-Earths orbiting in its 'habitable zone'.

"This is the region where temperatures ought to allow for the possibility of liquid water, although no-one can say for sure what conditions are really like on these planets....

"...Previous studies of Gliese 667C had established there were very likely three planets around it, with its habitable zone occupied by one super-Earth - an object slightly bigger than our home world, but probably still with a rocky surface.

"Now, a team of astronomers led by Guillem Anglada-Escude of the University of Göttingen, Germany, and Mikko Tuomi, of the University of Hertfordshire, UK, has re-examined the system and raised the star's complement of planets.

"The researchers used a suite of telescopes including the 3.6m telescope at the Silla Observatory in Chile. This incorporates the high-precision Harps instrument. Harps employs an indirect method of detection that infers the existence of orbiting planets from the way their gravity makes a parent star appear to twitch in its motion across the sky...."

It looks to me as if the artist who made that picture was thinking of Mars: which makes sense, since most of us have seen more pictures taken on Mars, than on any other planet besides Earth.

Maybe landscapes on one of those three planets does resemble what we've found on Mars: apart from having gravity that's a lot more than we're used to here on Earth. I'll grant that there's no way, as far as I know, of telling how strong gravity on Gliese 667C-c, f, and e are.

On the other hand astronomers are pretty sure that something that's more massive than Earth, but less massive than Neptune, is mostly rock and metal. That would make it very roughly as dense as the four innermost planets of the Solar system, and it follows that we'd feel a whole lot heavier if we stood on one of those newly-discovered worlds.

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3. Rocky, Maybe: Life, Could Be

(from PHL @ UPR AreciboOrbits, via Space.com)
"Orbits and approximate relative size of the planets around Gliese 667C (orbits and planets are not to scale with each other). All three potentially habitable planets (c, f, and e) orbit within the 'conservative habitable zone.' image released June 25, 2013."
(Space.com)

"Found! 3 Super-Earth Planets That Could Support Alien Life"
Miriam Kramer, Space.com (June 25, 2013)

"The habitable zone of a nearby star is filled to the brim with planets that could support alien life, scientists announced today (June 25).

"An international team of scientists found a record-breaking three potentially habitable planets around the star Gliese 667C, a star 22 light-years from Earth that is orbited by at least six planets, and possibly as many as seven, researchers said. The three planet contenders for alien life are in the star's 'habitable zone' - the temperature region around the star where liquid water could exist. Gliese 667C is part of a three-star system, so the planets could see three suns in their daytime skies.

"The three potentially rocky planets in Gliese 667C's habitable zone are known as super-Earths - exoplanets that are less massive than Neptune but more massive than Earth. Their orbits make them possible candidates for hosting life, officials from the European Southern Observatory said in a statement. [See images of the alien planets of star Gliese 667C] ..."

A key phrase in this article is "potentially rocky." The odds are probably pretty good that they're made of stuff that's similar to Venus or Earth. On the other hand, they could be mostly water; or something else. Eventually, astronomers will find a way to separate light from one of those planets from light coming from the stars: which means they'll be able to tell what color they are. That sort of spectroscopic analysis will tell at least roughly what the outer parts of the planets are made of.

Or, if development of tech that uses Alcubierre's math goes much faster than I think it will, someone may get there to collect samples first. And that's yet again another topic.

The Gliese 667 system isn't particularly bright, but it's close, so amateur astronomers could try spotting it. This star chart shows where to look.


(from PHL @ UPR AreciboOrbits, via Space.com)
"Gliese 667 is a nearby system of three stars that is easy to locate in the Scorpius constellation. The main two central stars Gliese 667AB are barely visible to the naked eye but easy to spot by binoculars or a small telescope. They are so close together that they appear as a single star. Gliese 667C is far enough from the central stars to be seen as separate star. However, it requires a larger telescope to be seem. Image released June 25, 2013."
(Space.com)

Folks at the European Southern Observatory published this photo of Gliese 667 and surrounding sky.


(from ESO, via Space.com)
"This picture shows the sky around multiple star Gliese 667. The bright star at the centre is Gliese 667 A and B, the two main components of the system, which cannot be separated in this image."
(Space.com)

Related posts:

• Planets and life
  • "Planets, Space-Time Bubbles, and Turtle Shells"
    (June 7, 2013)
    Particularly
    • Getting a Better Look at Kepler's Planets
    • Another Photo of a New Planet
  • "Robots, a Martian Dune, and Mapping a Billion Stars"
    (May 10, 2013)
    Particularly
    
    • Nifty Name, Oldish Idea
  • "DNA, Voyager 1, Habitable Worlds, and the Universe"
    (March 22, 2013)
  • "Seriously Searching for Life in the Universe"
    (February 8, 2013)
  • "Reason, Evidence, and Searching for Truth"
    (February 3, 2013)
• Getting there
  • "Warp Drive: Imagined and Real (Maybe, Eventually)"
    (May 24, 2013)
  • "Today, the Planets: Tomorrow, the Stars?"
    (May 17, 2013)
  • "Warp Drive: Silly as Thinking People can Fly"
    Apathetic Lemming of the North (May 17, 2013)
  • "Another Step Closer to a Practical Warp Drive: Maybe"
    Apathetic Lemming of the North (November 30, 2012)
  • "Antimatter Rocket Motor: Physics, Straightforward; Engineering, Not So Much"
    Apathetic Lemming of the North (October 26, 2012)
• Stewardship
  • "Designed as Stewards"
    (March 17, 2013)
  • "Ethics and Asteroids"
    (February 20, 2013)
  • " '...The Man With the X-Ray Eyes,' the Tuskegee Experiment, and Seeking God"
    (February 10, 2013)
  • "Advanced Technologies and Responsible Stewardship"
    (January 14, 2013)
  • "Earth Day, 2012: This Catholic's View"
    (April 22, 2012)
• Speculation, mostly
  • "Life in the Universe: Where is Everybody?"
    Apathetic Lemming of the North (March 15, 2013)
  • "Timing is Everything"
    Drifting at the Edge of Time and Space (October 7, 2009)
  • "Alien Life will Most Likely be - Alien"
    Drifting at the Edge of Time and Space (April 12, 2010)
  • "Gods, Demons, and Used Spaceship Dealers"
    Drifting at the Edge of Time and Space (February 13, 2010)
  • "Cloud Cities of Venus"
    Apathetic Lemming of the North (July 25, 2008)